This specification will be discussed in relation to its application to treatment of aortic arch disease, that is to treatment in the thoracic arch of a patient but the invention is not so limited and is applicable to any lumen of the human or animal body and particularly curved lumens.
Throughout this specification the term distal with respect to a portion of the aorta, a deployment device or a prosthesis such as a stent graft is intended to mean the end of the aorta, deployment device or from the heart and the term proximal is intended to mean the portion of the aorta, deployment device or end of the prosthesis nearer to the heart. For other lumens within the human or animal body the terms caudal and cranial respectively should be understood.
When deploying a stent graft which is substantially cylindrical in a curved aorta there is a danger that the proximal end of the stent graft, that is the end nearer the heart, will not lie flat against the walls of a aorta and blood flow can get underneath the edge of the graft particularly on the inner side of the curve of the thoracic arch and cause the stent graft to buckle and close off thereby causing serious problems.